This invention relates to a coffee extracting apparatus of a percolating type for extracting coffee essence from coffee material or powder by supplying hot water to the coffee powder.
As a coffee extracting apparatus of the type, use is conventionally made of a hot water feeding cylinder type extracting apparatus and an espresso extracting apparatus.
A conventional hot water feeding cylinder type extracting apparatus comprises an extracting container having an outlet opening for extracting coffee essence from coffee powder with being supplied with hot water of substantially normal pressure and elevated temperature. A filter member is used to cover the outlet opening of the receiving container and supported by a supported member in the manner known in the art.
However, the conventional hot water feeding cylinder type extracting apparatus is at a disadvantage in being unable to obtain the liquid coffee extract of amply high concentration because the operation thereof is devoid of a step of prewetting and steaming. It is further at a disadvantage in being unable to attain accelerated extraction of coffee essence because the hot water in the hot water feeding cylinder is forced by the hot water feeding piston into the extracting cylinder and consequently the rise of the pressure in the extracting cylinder is slow.
A conventional espresso extracting apparatus has a structure which will later be described in conjunction with the figure. The conventional espresso extracting apparatus is at a disadvantage in requiring the reheating device for accommodating the hot water of elevated temperature and increased pressure to be in a strong structure proof against pressure, further requiring the water heating device for heating the cold water of increased pressure to be in a structure proof against pressure, also necessitating provision of a water pump, a check valve, etc., and consequently entailing an high cost of equipment.